Cloth cutting machine



May 12, 1942.

M. zAwlrsTowsKl CLOTH CUTTING MACHINE Filed March 9, 1940 '2 Sheets-Sheet l jp-gz.

INVENTOR Mam@ Zea/www5 BY A a 7g. lu/@W14 ATTORNEYS May 12, 1942. M. zAwlsTowsKl CLOTH CUTTING MACHINE 2 Sheets-Sheet 2 Filed March 9, 1940 w Q// a a MW W ms 7 LJ o o@ w u 2 f1 8 5 36 3y 33 2 5 46 3 m1; a Q f. 4g 3 @W nl 2 W 2 7 WHY l. 5 l v 5 5 6 0 6 5 2 www of V a @o ww a V 0.o T O IT. 5 l 2 d l 5 6 ATTORNEYS Patented May 12, 1942 STATES PATENT- orrics 13 Claims.

The present invention relates to a mechanism for sharpening the reciprocating knifeof a clothcutting machine. Y

One object of the present invention is t provide a new and improved power driven knife sharpening mechanism of the above type, which can be operated selectively to produce either a very ne saw tooth or roughened cutting edge, or a substantially smooth and straight cutting edge.

Another object is to provide a knife sharpening mechanism, which may be operated along the knife while the latter is at rest or while it is being reciprocated at full speed.

Another object is to provide a cloth-cutting machine having a knife sharpening device, which may be operated to sharpen the knife without interference from the presser foot bar irrespective of .its position.

Another object is to provide a new and improved means for automatically moving the sharpening elements of a cloth-cutting machine away from the plane of the knife to be sharpened when said elements are moved upwardly beyond a predetermined distance, and for automatically moving said sharpening elements towards the plane of the knife to be sharpened, when said elements are moved downwardly from an inoperative elevated position.

Another object is to provide a knife sharpenv ing mechanism, which can be moved into close compact position with respect to the cloth-cutting machine when inoperative, so that it does not interfere with normal cutting operation of said machine, and does not render said machine bulky or unwieldy in operation.

Another object is to provide a knife sharpening mechanism, having new and improved means for yieldably urging the sharpening elements into sharpening contact with the'knife during sharpening operations.

Another object is to provide a new and improved knife sharpening mechanism, in which the sharpening elements are power driven automatically upon the downward movement of said elements beyond a predetermined positiornand in which the power drive to said sharpening elements is automatically cut oi upon movement of said sharpening elements upwardly beyond a predetermined position.

Various other objects of the invention will be apparent from the following particular description, and from an inspection of the'accompanying drawings, in which- Fig. 1 is a front elevation of a cutting machine, with a knife sharpening mechanism embodying the present invention shown in inoperative elevated position,

Fig. 2 is a side elevation of the machine shown in Fig. 1,

Fig. 3 is a front elevation of the machine, but showingthe sharpening mechanism during knife sharpening operation, y

Figs. 4, 5 and 6 are sections taken on lines 4 4, 5-5 and 6-6 of Fig. 1 respectively, but on a somewhat larger scale, and

Fig. '7 is a section taken on line 'I-l -of Fig. 3, on the same scale as Figs. 4 to 6, the sharpening elements being shown in full lines in knife sharpening position, and in dot and dash lines in inoperative position.

The knife sharpening mechanism is shown attached to a cloth cutting machine of the general type shown in my prior Patent No. 1,568,705, issued January 5, 1926. The working parts `of the illustrated machine are carried by a vertical standard I 0, the lower end of which is secured to a base Il adapted to slide beneath the layers of material to be cut. The standard I Il carries at its upper end a frame I2, to which is secured an electric motor I3, the casing of which has a handle I4 for guiding vand controlling the machine. The motor I3, which is controlled bya suitable switch I5, vertically reciprocates a clothcutting knife I6, guided in a groove or slot in the front edge of the standard IU. In front of this knife I6 .is a vertically adjustable guard bar 20, having a presserv foot 2| at its lower end.

The knife sharpening mechanism includes two Y desirably staggered as shown. These, grinding wheels 22 are driven from an electric motor 25, superposed on the knife operating motor I3, and

' suitably supported as for instance by means of a frame plate 26, formingthe head plate of both motor'casings. y

The transmission between the motor 25 and the grinding wheels 22 includes a pair of parallel upright shafts 28, suitably journalled in a pair of brackets 2l and 29, which are rigid with an eX- tend forwardly from the frame plate 25. The shafts 28 are driven simultaneously in opposite directions from the motor 25, desirably by means of a gearing comprising a worm 30, secured to the shaft of the motor 25, and meshing with worm wheels 3| which are splined on the two shafts 28, to permit said shafts to slide axially through said wheels without interruption of the drive to said shafts, and which are held by suitable thrust bearings between two superposed plates 32 constituting the upper bracket 21.

The transmission between each shaft 28 and its corresponding set of grinding wheels 22 desirably includes a rope pulley 33, mounted on the lower end of said shaft for rotation therewith, a rope pulley 34 mounted on the spindle 23 for rotation with the corresponding pair of grinding wheels 22, and a drive rope 35 between said pulleys.

The drive connection between the pulley k34 and, its corresponding set of grinding wheels 22 desirably comprises a sleeve extension 36 on said pulley, loosely encircling the respective spindle 23. The two grinding wheels 22 are spaced apart L by a washer 31, and are clamped for rotation with the pulley 34 and sleeve 36 by means of a nut 38, threaded to the lower'end of the sleeve 36, and bearing against a washer 39 on the lower side of the lower grinding wheel. Nuts 45 threaded on the lower end of the spindle 23 form a stop for the lower end of the sleeve 36. This arrangement permitsveasy assembly or disassembly of the two sets of knife sharpening elements.

The two sets of grinding wheels are bodily movable horizontally towards or away from knife sharpening position. For that purpose, each spindle 23 is suspended from the outer end of an arm 40, extending radially of its respective shaft 28, and rotatable about said shaft. A washer 4I spaces this arm 40 from the pulley 34.

For connecting the spindle 23 to its respective arm 40, in a manner to permit easy adjustment of said spindle lengthwise of said arm and easy mounting of said spindle, the outer end of said arm 40 is desirably bifurcated by an elongated slot 42 through which the upper end of said spindle 23 extends. A washer 43 seated on the arm 4D is held in position by a screw 44, threaded axially into the upper end of the spindle 23.

For rotatably supporting each arm 40, the inner end thereof is desirably affixed by pressfitting` or the like to a sleeve 41, which loosely encircles the lower end of its respective shaft 28,

and which is journalled in a cross-bar 48 encir- L cling both shafts 28. The arm 40 is desirably spaced from the lower end of this cross-bar 48 Vby a collar B rigid with the sleeve 41.

v Means are provided for effecting vertical movement of the two sets of grinding wheels 22 by manipulation of the cross-bar 48.

This means desirably includes a cylindrical member in the form of a sleeve 55, loosely encircling each shaft 28 just above the cross-bar 48, and encircling at its lower end a reduced portion of the sleeve 41. This sleeve 55 is made rigid with the sleeve 41 by any suitable means such as a set screw 56, so that both sleeves, the collar 5I] and the arm 46 rotate as a unit about their respective shaft 28, and with respect to the cross-bar 43, and move vertically as a unit with said cross-bar.

Upward vertical movement of the cross-bar 48 is transmitted to the shafts 28 through the sleeves 41 and shoulders 58 on said shafts respectively, while downward Vertical movement of said crossbar is transmitted through the pulleys 33 and to said shafts in a manner to be hereinafter made apparent.

A finger piece 60 secured to the front side of the cross-bar-48 facilitates vvertical manipulation of said bar. This manipulation of the bar 48 moves the shafts 28 vertically as already described, and causes corresponding movement of the two sets of grinding wheels 22.

Means are provided for automatically swinging the two sets of grinding wheels 22 in opposite directions towards knife-grinding position shown in full lines in Fig. '1 when said wheel sets are moved downwardly within a given range, and for automatically swinging said sets towards the inoperative position shown in dot and dash lines when said sets arev moved upwardly in said range, For that purpose, each sleeve 55 is comparatively long and has a high pitch spiral groove 6I into which extends a roller 62 supported from the frame plate 26. As the sleeves 55 are moved Vertically by manipulation of the cross-bar 48, they are rotated about their respective shafts 28 by the rollers 62. Each arm 48 being rigid with its corresponding sleeve 55 will rotate therewith between the two positions indicated in Fig. 7. The spiral grooves 6I in the two sleeves 55 are similar in pitch, but extend in opposite directions, so that the two sets of grinding wheels 22 will swing simultaneously and equally but in opposite directions.

The spiral drive groove 6I starts from the upper end of the sleeve 55, and extends through about 180, so that when the sleeve is in'uppermost limiting position as shown in Fig. 4, the arm 40 extends forwardly of the cutting machine as shown in dot and dash lines in Fig. 7. When the sleeves 55 are lowered into position in which the rollers 62 just emerge from the upper open ends of their respective drive grooves 6I, the arms 4I] will have been rotated to approximately the position shown in full lines in Fig. '7 with the two sets of grindingwheels 22 almost touching opposite sides of the knife I 6.

The two arms 40, in grinding position shown in full lines in Fig. '1, extend on opposite sides of the presser foot barV 20, which is offset with respect to the plane of the knife I6. To prevent this bar from interfering with the inner run of the rope belt nearest thereto, and to permit the operation of the sharpening device while the presser foot bar is lowered in operative position, said inner belt run is held back by an idler 59, suspended from the lower side of the corresponding arm 40.

Means are provided for yieldably urging the two sets of grinding wheels 22 into grinding contact with opposite sides of the cutting edge of the knife I6. This desirably includes a friction washer 63 of hard rubber or the like, disposed between each bar and its corresponding drive pulley 33, both the washer and the pulley being keyed on its respective shaft 28 for instance by making a lower section 64 of said shaft of rectangular cross-section. The washer 63 and pulley 33 are spring-pressed upwardly by means of a coil spring 65, so that said washer is pressed against the under side'of the arm 40. As the pulley 33 and the washer 63 are positively rotated, the arm 40 is frictionally rotated towards the knife I6, and yieldingly pressed against it. The tension of the spring 65 and rotative force applied to the arm 40 may be adjusted by means of a nut 66 on the lower end of the shaft.

The frictional drive to'the arms 40 is not effective until the sleeves have been moved downwardly below the rollers 62 and said sleeves are free to rotate. When the sleeves 55 have been so released, the grinding wheels will be almost in contact with the cutting edge of the knife I6, and

the frctional drive from the rotating drive pulleys 33 through the washers 63 will yieldably maintain the rotating grinding wheels in grinding contact with the cutting edge. While the wheels 22 are urged in grinding contact with the cutting edge of the knife I6, they are reciprocated by manipulation of the cross-arm 48 through the finger piece 68 as already described.

During knife grinding action, the reciprocating sleeves 55 will be maintained substantially in the same rotative position in which they were when the rollers 62 first emerged from their spiral drive grooves 6I, so that the upper open ends of these grooves will be in vertical alignment with the rollers, and ready to receive the rollers 62 when said sleeves are moved upwardly towards inoperative position of the grinding wheels. The wheels 22 are desirably urged towards the inoperative position by means of a spring 61, anchored at its upper end to the bracket 29 and secured at its lower end to the cross-arm 48.

The motor 25 is desirably operated automaticcally by a limit switch in accordance with the vertical position of the grinding wheels 22. For that purpose, there is provided a trip switch 'Ill in the path of travelV of a finger 'II projecting from the rear side of the cross-arm 48. As this cross-arm 48 is moved upwardly near the inoperative position shown in Fig. 4, it trips the switch 10, so that the motor 25 is shut off. When the cross-arm 48 is moved downwardly from this inoperative position, the finger 'Il tripping the z witch 'I2 will turn on the current to the motor 25.

Although the operation of the sharpening deice is believed apparent from the foregoing description, this operation is briefly summarized.

While the sharpening device is in the elevated inoperative position shown in Fig. 4, the motor 25 is shut oif, the arms 40 extend forwardly of the cutting machine in front of the motors I3 and the knife I6, and the stationary grinding wheels 22 are in raised position above the operating field of the knife and out of the cuttingV path thereof, so that cloth-cutting operations can be eiected without interference from said sharpening device.

When it is desired to sharpen the knife I6, the operator, by means of the finger piece 60, pushes the cross-bar 48 downwardly against the action of the spring 61. At the beginning of the downward movement, the switch 'I0 is tripped by the finger 1I and the motor 25 is started. The motor 25, driving through the shafts 28 and rope drive 33, 34 and 35, rotates the two sets of grinding wheels 22 at high speed and in opposite directions indicated in Fig. 7. n

During the resultant downward movement of the sleeves 55, they are rotated in opposite directions through the spiral groove BI and roller drive 62, so that the arms 48 and the two sets of the grinding wheels 22 are swung in opposite directions about the shafts 28 from the position shown in dot and dash lines in Fig. 7 towards the knife I6. When the sleeves 55 reach a position where the rollers 62 emerge from the upper ends of their respective spiral grooves 6 I, the arms 48 will have rotated about 180, and the two sets of grinding wheels 22 will be nearly in grinding contact with opposite sides of the cutting edge of the knife as shown in full lines in Fig. 7. The downward movement of the cross-bar 48 is continued beyond this point, so that the friction drives to the arms 40 from the pulleys 33 and through the washers 63 yieldably urge the grinding wheels 22 against the knife I6. This grinding pressure of the wheels 22 against the knife I6 continues while said wheels are reciprocated up and down along the cutting edge by raising and lowering the finger piece 66. While in this grinding position, the wheels 22 are prevented from accidentally coming in contact with the frame I2, since upward movement of the sleeve 55, beyond a point where the rollers 62 enter their respective spiral grooves 6I, will rotate said sleeves and swing the two sets of grinding wheels 22 away from the knife I6 and forwardly of the cutting machine.

As the reciprocation and rotation of the grinding wheels 22 is effected by a different motor than that which effects reciprocation of the knives, the knife sharpening action may be effected either while the knife is stationary or while it is reciprocated by the motor I3. The motor I3 may be started or stopped by its switch I5 independently of the starting or stopping of the motor 25 by its switch 10. If the sharpening operation is effected while the knife I6 is stationary, a series of fine saw teeth or a roughened edge will be formed on the cutting edge. Sharpening operation effected during reciprocation of the knife I6 will produce a smoother cutting edge on said knife.

After termination of the knife grinding operation, the cross-barv 48 is moved upwardly into inoperative position shown in Fig. 4, to shut off the motor 25 and swing the grinding wheels 22 into position forwardly of the cutting machine.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope of the claims, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a cloth-cutting machine of the type having a motor, and a knife below said motor reciprocally driven thereby, a sharpening device for said knife comprising a pair of sharpening wheels, means for driving said sharpening wheels at high speed for knife sharpening action, and including a pair of upright axially movable shafts disposed in front of said motor, means for driving said shafts, and drive connections between said shafts and said wheels and a pair of substantially horizontal arms supported on said shafts for swinging movement about the axes thereof, and movable with said shafts axially thereof, said arms supporting said grinding wheels` respectively, and being swingable in opposite directions about said axes to move said grinding wheels towards or away from sharpening contact with opposite sides of the cutting edge of said knife, said shafts being rotatable with respect to their corresponding supported arms to permit drive to said Wheels through said shafts while said wheels are in knife sharpening position.

2. In a cloth-cutting machine of the type having an upright knife, a sharpening device for said knife comprising a sharpening wheel, said wheel being movable towards and away from sharpening contact with said knife, a source of power for rotating said wheel, a transmission between said source of power and said wheel for rotating said wheel for knife sharpening op erations, and a friction drive for yieldably urging said wheel in sharpening contact with said knife.

3. In a cloth-cutting machine of the type having an upright knife, a sharpening device for said knife comprising a grinding wheel, a' drive to said wheel for rotatingV said wheel, and including a shaft, and a drive wheel rotatable with said shaft, an arm mounted on said shaft for movement thereabout and supporting said grinding wheel, said arm being positioned to move the grinding wheel towards or away from sharpening contact with said knife, and friction means rotatable with said shaft and having friction drive contact with said arm and said driving wheel, whereby said grinding wheel is yieldably urged into sharpening contact with said knife.

4. In a cloth cutting machine of the type having an upright knife, a sharpening wheel mounted with its axis upright, means for rotating said wheel at high speed about its own center for knife sharpening operations, and including an upright shaft, means for driving said shaft, and a transmission between said shaft and said wheel, an arm supporting said wheel away from said shaft and mounted for rotation with respect to and about said shaft to swing said wheel from inoperative position into sharpening contact with the cutting edge of said knife, and means guiding said wheel for movement along said knife while in sharpening contact therewith and while said wheel is being driven at high speed through said shaft.

5. In a cloth cutting machine of the type having an upright knife, a sharpening wheel mounted with its axis upright, an upright shaft, a positive drive for said shaft, a, friction drive between said shaft and said wheel for rotating said wheel at high speed about its center for knife sharpening operations, and an arm supporting said wheel away from said shaft and mounted for rotation about said shaft to swing said wheel from inoperative position into sharpening contact with the cutting edge of said knife, said arm being movable along the axis of said shaft to move said wheel along said knife while in sharpening contact therewith, said shaft being rotatable with respect to said arm to permit drive to said wheel through said shaft while said wheel is in knife sharpening position.

6. In a cloth cutting machine f the type having an upright knife, a sharpening wheel, a shaft, means for driving said shaft, a transmission between said shaft and said wheel for rotating said wheel at high speed about its center for knife sharpening operations, an arm supporting said wheel and pivotally mounted to swing said wheel from inoperative position into sharpening contact with the cutting edge of said knife, and a friction drive between said shaft and said arm urging said arm into rotative position to yieldably press the rotating wheel against said knife.

7. In a cloth cutting machine of the type having an upright knife, a sharpening wheel, means supporting said sharpening wheel for swinging movementtowards or away from sharpening contact with the cutting edge of said knife, a shaft, means for driving said shaft, a friction drive between said shaft and said wheel for rotating said wheel at high speed about its center for knife sharpening operations, a friction clutch between said shaft and said supporting means for yieldably urging said wheel into sharpening contact with said knife, and means guiding said supporting means for up or down movement to effect movement of the` rotating wheel along said knife while in sharpening contact therewith.

8. In a cloth cutting machine of the type having an upright knife, a. sharpening wheel mounted with its axis upright, an upright shaft, means for driving said shaft, a transmission between said shaft and said wheel for rotating said wheel at high speed about its 'center for knife sharpening operations, an arm supporting said wheel away from said shaft and mounted for rotation about said shaft to swing said wheel from inoperative posititon into sharpening contact with the cutting edge of said knife, a friction clutch between said shaft and said arm urging said arm into rotative position to yieldably press the rotating wheel against said knife, and means guiding said arm for up or down movement to effect movement of the rotating wheel along said knife while in sharpening contact therewith.

9. In a cloth cutting machine of the type hav- .ing an upright knife, an upright shaft, means for driving said shaft, an axially movable cylindrical member rotatably encircling said shaft and having a spiral drive groove, a fixed member extending in said groove and serving to rotate said cylindrical member as it is moved axially, a crank arm rotatable with said cylindrical member, a knife sharpening wheel supported on said crank arm and swingable therewith upon axial movement of said cylindrical member, to move the wheel towards or away from sharpening position with respect to said knife, and a drive between said shaft and said wheel for rotating said wheel at high speed while in sharpening contact with said knife.

l0. In a cloth cutting machine of the type having an upright knife, an axially movable upright shaft, means for driving said shaft while said shaft is moved axially, a cylindrical member rotatably encircling said shaft and movable axially with said shaft, said member having a spiral drive groove, a fixed member extending in said groove and serving to `rotate said cylindrical member as it is moved axially, a crank arm rigid with said cylindrical member, a knife sharpening wheel supported on said crank arm and swingable therewith about said shaft upon axial movement of said cylindrical member whereby said wheel can be moved towards or away from sharpening position with respect to said knife, and a drive between said shaft and said wheel for rotating said wheel at high speed while in sharpening contact with said knife.

11. In a cloth cutting machine of the type having anupright knife, a pair of upright parallel shafts, a fixed motor having a substantially horizontal shaft extending between said upright shafts, a transmission between said motor shaft and said upright shafts for rotating said latter shafts in opposite directions, a pair of knife sharpening wheels, drive connections between said upright shafts and said wheels respectively for driving said wheels at high speed in opposite directions for knife sharpening operations, and means supporting said wheels for swinging movement bodily in opposite directions towards or away from sharpening contact with opposite sides of the cutting edge ofsaid knife, said supporting means being movable in a direction to move said wheels along said knife while in sharpening contact therewith.

12. In a cloth cutting machine of the type having a motor with a substantially horizontal shaft and an upright knife below said motor and reciprocally driven from said shaft, a fixed motor for rotating said latter shafts in opposite directions, a pair of knife sharpening wheels, drive connections between said upright shafts and sai-d wheels respectively for driving said wheels at high speed in opposite directions for knife sharpening operations, and means supporting said wheels for swinging movement bodily in opposite directions towards or away from sharpening contact with opposite sides of the cutting edge of said knife, said supporting means being movable in a direction to move said wheels along said knife while in sharpening contact therewith.

13. In a cloth-cutting machine of the type having an upright reoiprocable knife, a sharpening device for said knife comprising a pair of grinding wheels, means for driving said grinding.

wheels at high speed for knife sharpening operations and comprising a pair of upright shafts, means for driving said shafts, and drive connections between said shafts and said wheels, a pair of arms supporting said wheels, a sleeve connested to each of said arms for rotation therewith, and encircling a respective shaft, said sleeves being movable up and 'down along the axes of their respective shafts and rotatable in opposite directions about said axes, to bring said grinding wheels from an inoperative position to a position in sharpening contact with opposite sides of the cutting edge of the knife, said shafts being rotatable with respect to their encircling sleeves to permit drive to said wheels through said shafts while said Wheels are in knife sharpening position.

MARTIN ZAWISI'OWSKI. 

